Numerical simulation of stress-strain state of pipeline under heaving of ground

Abstract

The main pipelines in permafrost areas are exposed to various exogenous processes, for example, frost heaving. In the work, values of frost heaving of various types are shown by mathematical modeling. Numerical realization of the problem of heat and moisture transfer process is carried out by a scheme with directed differences considering the sign of the speed of groundwater infiltration. For the computational experiment, initial parameters for heat and moisture transfer at a base of the pipeline are defined in relation to natural and climatic conditions of Central Yakutia. In the presence of groundwater, the heaving of an injection type is formed. Over time, frost injection of the injection type increases, which leads to a change in the value of the coefficient of unevenness. It is shown that the stress state of the pipeline as a result of frost heaving gradually transforms into plastic deformation. With the help of the pipeline fold equation, the stress-deformed state of the pipeline is estimated from the amount of migration heaving. The heaves are associated with a multi-year «seasonal loosening», which can lead to low-cycle fatigue failures.